Mapping near-inertial variability in the SE Bay of Biscay from HF radar data and two offshore moored buoys

• Published in: Geophysical research letters Vol. 38; no. 19
• Main Authors: Rubio, A., Reverdin, G., Fontán, A., González, M., Mader, J.
• Format: Journal Article
• Language: English
• Published: Washington, DC Blackwell Publishing Ltd 01.10.2011; American Geophysical Union; John Wiley & Sons, Inc
• Subjects: Bay of Biscay; Buoys; continental slope; Earth Sciences; Earth, ocean, space; Exact sciences and technology; Geophysics; near-inertial currents; Oceanography; Offshore; Offshore engineering; offshore moorings; Offshore structures; Oscillations; Physical oceanography; Physics; Radar; Sciences of the Universe; Summer; Three dimensional; Bay of Biscay; Atlantic Ocean; North Atlantic; Buoy; kinetic energy; maps; Mooring; Surface current; Inertial wave; Summer; cartography; Velocity distribution; slopes; variability; buoyancy; offshore; Four dimensional models; shelf-slope break; Winter; Radar observation; Forcing; radar methods; oscillations; seasonal variations
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2011GL048783

HF radar surface current data together with data from two operational offshore oceanographic buoys located over the slope are used to map the variability associated with the near‐inertial waves, during a target year (2009), in the SE Bay of Biscay. The results obtained show the complex 4D distribution of inertial oscillations in this area. We find a very pronounced horizontal structure across the area with ranges of a factor 5 in near‐inertial kinetic energy. This pattern presents also strong seasonal variability, with a peak in KE closer to the shelf‐break in summer, whereas winter maximum is weaker and located further to the north‐east. The mooring data indicate more trapping near the surface in summer. These patterns are discussed in relation to the known seasonal differences in atmospheric/buoyancy forcing and the characteristics of the sub‐inertial surface velocity field. Key Points Document the time‐evolving 3D structure of NI oscillations in a coastal region An effective approach to observe NI oscillations by HF radar and in‐situ data Provide hypotheses on the processes modulating the structure of NI oscillations